[PATCH 1/2] x86: optimize XCHG to MOV for same-register forms

[Christian Ludloff]

> Assembler optimization is intended primarily for hand-written code.

Uhm, hand-written assembler code is the prime example
for *not* wanting specified instruction FOO suddenly turn
into emitted instruction BAR.

If I code XCHG, then I mean to get XCHG. Had I wanted
MOV, I'd have coded MOV.

What is the expected worthwhile benefit of the proposed
transformations in practice?

--
C.